Tobacco threshing apparatus and method

ABSTRACT

A tobacco thresher includes two systems of rotating teeth each of which intermeshes with a separate rotating disc system. The disc systems comprise separated coaxial rotating discs which have pins mounted on the sides thereof. The teeth rotate at a greater angular velocity than their associated rotating disc systems; and the angular velocities of the two rotating disc systems can be independently varied. The teeth are elongated to drive the tobacco along a path while the tobacco is simultaneously restrained by the movable pins which are disposed in a cross-wise attitude with respect to the teeth.

United States Patent Smith, Jr.

[54] TOBACCO THRESHING APPARATUS AND METHOD [72] Inventor: Robert A. Smith, Jr.,- Richmond,

[73] Assignee: Superior Tobacco Machinery &

Sheet Metal, Inc., Richmond, Va.

[22] Filed: July 2, 1970 [21] Appl. No.: 51,881

[52] US. Cl ..131/145, 146/122 [51] Int. Cl. ..A24b 05/10 [58] Field of Search ..131/145, 146; 130/30 B; 241/136; 146/122 [56] References Cited UNITED STATES PATENTS 2,789,564 4/1957 Hunter .....l31/l45 296,445 4/1884 Phillips... ....l46/l22 X 908,801 1/1909 Ponsar ..l46/122 1,403,489 1/1922 Deubel ..131/145 1451 Dec. 19,1972

631,946 8/1899 .Baker ..130/30 B 1,337,127 4/1920 Friedrich ..130/30 B UX 2,150,493

-3/l939 Dahlstrometal. ..131/145 Primary Examiner-Robert W. Michell Assistant Examiner.l. F. Pitrelli Attorney-Griffin, Branigan & Kindness [57] ABSTRACT A tobacco thresher includes two systems of rotating teeth each of which intermcshes with a separate rotating disc system. The disc systems comprise separated coaxial rotating discs which have pins mounted on the sides thereof. The teeth rotate at a greater angular velocity than their associated rotating disc systems; and the angular velocities of the two rotating disc systems'can be independently varied.

The teeth are elongated to drive the tobacco along a path while the tobacco is simultaneously restrained by the movable pins which are disposed in across-wise attitude with respect to the teeth.

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BY Era/u nan 44m ATTORNEYS TOBACCO THRESHING APPARATUS AND METHOD BACKGROUND OF THE INVENTION ten them and give them a desired limpness in preparam tion for a tobacco thresher which'removes the stems from the lateral foliage of the leaves. A mixture of stems and leaves is then passed to a separator from which the pieces of lateral foliage are delivered toa shredder for cutting the foliage into strips in preparation for making cigarettes.

One popular prior art tobacco thresher comprises sets of stationary teeth and radially-extending rotating teeth which rotate about an axis withina cylinder housing. The stationary teeth areattached to the inner surface of the cylinder housing and intermesh with the rotating teeth. The bottom of the cylinder housing is made up of a series of gauging rollers which have gauging openings of a desired size therebetween.

In operation, whole tobacco leaves are fed from a conditioner into the cylinder housing where the rotating teeth intermesh with the stationary teeth to pull the leaves through the stationary teeth. In this regard, the leaf stems are tougher than the lateral foliage and tend to hang on to either the rotating or stationary teeth while the lateral foliage is stripped from the stems. The tobacco leaves remain in the cylinders and are continually cut until they are reduced to pieces of a size which pass through the gauging openings between the gauging rollers in the bottom of the cylinder housing. Examples of such prior art tobacco threshers are disclosed in U. S. Pat. Nos. 2,760,492 and 3,126,014.

One difficulty with many prior art tobacco threshers is that they cut lateral foliage into'irregularly shaped pieces. This difficulty can be more clearly understood with reference to FIGS. 1 and 2 which respectfully illustrate irregularly shaped pieces of lateral foliage and a regularly shaped piece of lateral foliage. Fines are created when irregularly shaped pieces of foliage are shredded along shredding lines as illustrated in FIG. 1; but fewer fines are created when regularly shaped pieces of foliage are shredded as illustrated in FIG. 2. Hence, because longer strips bring a higher market price than fines, it is an object of this invention to provide a tobacco thresher which cuts lateral foliage into regularly shaped pieces.

After being separated from lateral foliage, tobacco leaf stems are sometimes flattened and then shredded to form a lower grade of tobacco strip. Hence, it is desirable that a tobacco thresher sever most lateral foliage from the leaf stems so that undue amounts of foliage will not be placed with the stems and thereby be put to less profitable use than if placed with foliage. It is therefore another object of this invention to provide a tobacco thresher which does not leave an undue amount of foliage on the stems.

Another problem encountered of many prior art tobacco threshers is that they create pieces of foliage which vary greatly in size. The reason some prior art tobacco threshers do this is that their rotating teeth continually drive pieces of tobacco leaves through stationary teeth until the pieces have been cut down to the proper size to pass through the gauging openings. If, upon reaching the bottom of the cylinder housing, a piece of tobacco leaf is too large to pass through the gauging openings, it is carried upwardly around the cylinder and back through two series of stationary teeth where it is cut into pieces which are much smaller than desired. In this respect, it is desirable to cut most of the pieces of lateral foliage to a desired size before they reach the bottom of the cylinder the first time so that they will pass through the gauging openings rather than go back around the cylinder again to be cut into undesirable smaller pieces. Hence, it is another object of this invention to provide a tobacco thresher which cuts a large percentage of tobacco leaf pieces to a desired size before they reach the gauging openings a first time.

Still another limitation of prior art tobacco threshers is that they have unduly restrictive capacity ranges. For example, some prior art tobacco threshers which normally operate at around 10,000 pounds per hour cannot properly function at either above 12,000 pounds per hour or below 7,500 pounds per hour. In this regard, prior art tobacco threshers are choked when they exceed their upper limits; and do not adequately remove the stems from the leaves when they are operated below their lower capacities. These capacity limitations are particularly troublesome because an entire production line must often be shut down when there are relatively minor changes in the amounts of tobacco fed to a given production lines thresher. The upper capacity of a thresher can be increased to some extent by increasing the rotational speed of the teeth, but this results in excessive fines; and there is little that can be done to extend the lower limit. Hence, it is another object of this invention to provide a tobacco thresher which operates over a wide capacity range so that it can both maintain high production and continue in operation even though the tobacco input rate falls below the lower limits of prior art machines.

In addition, prior art tobacco threshers require relatively high-power drive motors even though they have low capacities as compared with threshers of the invention. It is therefore another object of this invention to provide a tobacco thresher that is more efficient and can be operated at a higher capacity with less power than a comparably sized machine of the prior art.

Yet another problem encountered with many prior art tobacco threshers is that an undue amount of wear is produced on the contact sides of the stationary teeth. Not only are stationary teeth relatively expensive,.but their replacement usually requires a full day during which the related production line must be shut down;

and in some cases, it is necessary to change stationary teeth as often as three times a season. It is therefore still another object of this invention to provide a tobacco thresher which not only has easily replaceable cutting surfaces, but wherein the surfaces ar less prone to wear and, therefore, do not require such frequent replacement.

SUMMARY OF THE INVENTION In accordance with principles of the structural aspects of this invention, the apparatus includes rotating teeth or blades (which are similar to those of the prior art); rotating discs having pins thereon (which are in lieu of the prior arts stationary teeth); and convenanun 1 AAA tional gaging rollers and openings located at the bottom of a thresher cylinder.

In the preferred embodiment of the invention, dual threshing systems are integrated into a single threshing machine. The operating speeds of the dual threshing systems can be independently varied in order that the threshing machine can create a mixture of sizes of lateral foliage pieces.

In operation, the rotating teeth intermesh with both the pins and the rotating discs which rotate at a lesser angular velocity than the teeth. In this manner, the tobacco leaves are pushed by the rotating teeth in a circular path through the rotating discs and their associated pins so that the teeth, discs, and pins cooperate to both remove leaf stems from lateral outgrowth and quickly cut the outgrowth into pieces of a desired size.

The new method of threshing tobacco comprises the step of driving tobacco leaves along a path by means of elongated teeth and simultaneously restraining the motion of the leaves with moving pins which are disposed in a transverse attitude with respect to the elongated teeth. More particularly, the path of the teeth is circular and the transverse pins rotate in another separate circular path.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects, features and advantages of this invention will be apparent from the following more particular description of a preferred em bodiment of the invention as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon clear illustration of the principles of the invention.

FIGS. 1 and 2 are schematic representation of pieces of tobacco leaf lateral foliage;

FIG. 3 is a pictorial view of a tobacco thresher employing principles of the invention;

FIG. 4 is a side cut-away view of the tobacco thresher illustrated in FIG. 3;

FIG. 5 is a view of rotating teeth and rotating discs taken along the lines ,5-5 in FIG. 4;

FIG. 6 is a schematic representation of a power drive system used to drive the tobacco thresher shown in FIGS. 3-5; and,

FIG. 7 is an enlarged side view of a set of rotating teeth passing through a rotating disc system.

DESCRIPTION OF A PREFERRED EMBODIMENT A preferred embodiment of this invention employs two thresher systems, A and B, separated by a dashed line in FIG. 4. The respective parts of the A thresher system are designated by numerals having A" as a suffix; and the parts of the B thresher system are designated by corresponding numerals followed by B- The tobacco thresher of FIGS. 3-7 comprises an outer housing (FIGS. 3 and 4), rotating tooth systems l7A and 17B, rotating disc systems 19A and 19B, and gauging roller systems 21A and 21B. Tobacco enters the outer housing 15 through a chute 11 and is threshed by cooperation between the tooth systems 17 and the respective rotating disc systems 19. Pieces of the thusly threshed tobacco are respectively gauged by the rollers 21 to insure that they are small enough before leaving the thresher.

The outer housing .15 is large enough to enclose the two separate but coordinated threshing systems A and B and has an inlet opening 25 at its top for receiving whole tobacco leaves from inlet chute 11. Access doors 27 are mounted on hinges 29 to form an upper portion of an outer housing and allow access to the rotating disc and tooth systems.

Each rotating tooth system comprises teeth 35 and coaxial circular plates 33 mounted on a drive shaft 31. The teeth 35 extend radially away from their drive shaft 31 and are arranged in linear sets located apart. One tooth set 37A is illustrated in FIG. 3; and the separation of each circular plates teeth can be seen in FIG. 4.

The teeth 35 are approximately 1 inch wide, V4 inch thick, and have dull tungsten hardened cutting edges 36.

As seen in FIG. 4, the tooth systems 17A and 17B are suitably spaced about the perimeters of their circular plates 33 so that they neither strike each other nor the other circular plates as they are rotated.

As shown in FIG. 5, some of the circular plates such as 39 have three teeth mounted thereon. Other circular plates 40 serve as spacers to maintain a proper spacing between plates 39.

Each roating disc system 19 comprises a drive shaft 41 and coaxial rotating discs 43 each having pins 45 extending outwardly from both sides thereof. The rotating disc system 19A rotates in a counterclockwise direction as shown in FIG. 4 and the rotating disc system 19B rotates in a clockwise direction; and the angular velocities of the two disc systems are less than the rotating velocities of their associated rotating blade systems 17.'In the illustrated embodiment, six pins 45 are disposed opposite each other at 60 intervals on each side of each rotating disc 43. As shown in FIG. 5, the pins of adjacent discs are not necessarily in line with one another. For clarity, the pins on the backsides of the rotating discs 43 in FIG. 5 are not shown. The pins of adjacent discs which extend toward one another are approximately one inch long and have open spaces 47 of approximately one and threequarter inches between their respective tips. The pins 45 and outer edges of rotating discs 43 are also covered with a dull, but hard tungstun facing 46 (FIG. 5).

The disc system drive shafts 41 (FIG. 4) are parallel to the tooth system drive shafts 31; and positioned and so aligned so that the rotating teeth 35 pass through the open spaces 47. Thus, the teeth 35 and discs 43 intermesh with one another.

The gauging roller systems 21 include drive shafts 49 disposed in arcs below the A and B threshing systems;

and rollers 51 mounted on the shafts 49 to define gaug ing openings 53. In this regard, the rollers 51 are turned by the shafts 59 in the direction shown by the arrows in FIG. 4.

FIG. 6illustrates a thresher drive system. Therein, a clockwise rotating motor-drive pulley 55 is driven by a motor 56. The pulley 55 drives a tooth-drive belt 57 which is tensioned by an idler pulley 59 and drives tooth-drive pulleys 58A and 588 in clockwise andcounterclockwise directions, respectively. Intermediate pulleys 61A and 61B rotate with their corresponding pulleys 58A and 588 to cause associated belts 62A and 623 to drive intermediate disc pulleys 63A and 63B. The intermediate disc pulleys 63A and 63B are connected to gear boxes 64A and 64B, respectively, which contain gears (not shown) for driving disc-drive pulleys 65A and 658. The disc drive pulleys 65A and 658, in turn, drive roller belts 67A and 678 which are tensioned by idler pulleys 71A and 71B and drive the various rollers in the directions indicated in FIG. 6.

In the-drive system of FIG. 6, gear shift sticks 73A and 73B are usedto adjust the driving ratios of the gear boxes 64A and 648 to vary the angular velocity ratios between a given disc-drive pulley 65A and 65B and its associated tooth-drive pulley 58A and 58B. In another embodiment, thegears in boxes 64 are actually replaced rather than shifted. Thus, the gear ratio of the gears in box 64A may be different from the ratio of the gears in box 648. In this manner, disc system 19A can have a different angular velocity than disc system 19B. The significance of having different angular velocities for .the A and B rotating disc systems will be explained shortly.

In another embodiment of the invention (not shown) the tooth-drive pulleys 58 and disc-drive pulleys 65 are driven independently of one another so that the angular velocities of the various pulleys can be independently adjusted.

In operation, whole tobacco leaves are fed from the inlet shoot 11 into inlet opening 25 and fall upon circular plates 33 and teeth 35. The teeth 35A drive the whole tobacco leaves in a clockwise direction inside A of the thresher toward the rotating disc system 19A. The teeth 35B drive other whole tobacco leaves in a counterclockwise direction toward disc system 19B. In this 'manner, the rotating teeth 35 drive the whole tobacco leaves into the disc systems 19 and then pass through the open spaces 47 (FIG. 5) between the pins 45 and adjacent rotating discs as explained above.

FIG. 7 illustrates a set of rotating teeth 35 as it passes through a rotating disc system 19. In this regard, the illustration is of teeth and discs in section A of the thresher, but for purposes of clarity, the suffixes are not shown. Therein, three pins 45a, 45b, and 45c are illustrated in three time positions 1, 2, and 3. As a whole tobacco leaf is driven by the rotating teeth 35, it is subjected to being cut by the pins 45 and the outer edges 44 of the discs 43. The interaction between the pins 45 and the teeth 35 separates the lateral foliage of the whole tobacco leaves from their stems and cuts up the lateral foliage into a desired size.

It should be especially noted that when the elongated teeth 35 and pins 45 pass one another, they are not disposed parallel to one another as are the cutting instruments of most prior art tobacco threshers. Instead, the axis of each pin is disposed in a plane that is perpendicular to the plane of the tooth which happens to be passing at any given time.

The threshed stems and pieces of lateral foliage pass through the gauging openings 53 and are discharged from the thresher through the discharge conduit 13. Normally, once a given leaf is driven through a disc system 19, it is cut up into the proper size to pass through the gauging openings 53. However, pieces which are not cut to the proper size are rolled-by openings 53 by the gaging roller systems 21 and into the middle of'the thresher where they are picked up by the rotating teeth 35 and carried upwardly back through the rotating disc systems 19.

In the above respect, a tobacco thresher employing principles of this invention, cuts up lateral foliage into smaller pieces if there is a decrease inthe angular velocities ratios of the rotating tooth systems to the rotating disc systems. In normal operation, these tooth system ratios are approximately 5, but it has been found that they can be varied over a range of from about 2.5 -to 7.5 and still obtain satisfactory results. Furthermore, the tooth/disc system ratios of the A and B thresher systems can be made to differ from one another by varying the ratios of the gear boxes 64. In this manner, two sizes of lateral foliage pieces can be created at the same time. Thus, a mixture of sizes of lateral foliage pieces is discharged from the thresher through the discharge conduit 13.

Although the interaction between the rotating teeth, the rotating discs, and the pins is not fully understood at this time, some observations can be made based on extensive experimental data on a thresher of the type described above. In this regard, the thresher separates the lateral foliage from the stems more efficiently and leaves less lateral foliage on the stems than do most commercially available tobacco threshers.

Secondly, the thresher of the invention cuts up lateral foliage into pieces which are generally more regular in shape than those cut by prior art threshers. Thus, the thresher of the invention produces fewer fines. In addition, the thresher of the invention produces less undesirable size variation while at the same time permitting a controlled mixture of pieces having specifically desired sizes.

The invention also permits a capacity range that is significantly wider than those of presently available threshers. For example, a given prior art thresher cannot effectively operate above 12,000 pounds per hour nor below 7500 pounds per hour. A comparable thresher employing the principles of the instant invention, however, has a lower capacity limit of 4000 pounds and was operated at as high as 13,000 pounds per hour. In this regard, however, the upper capacity limit has not yet been established experimentally because the maximum capacity of the available separators and shredders was only 13,000 pounds per hour. It is estimated, however, that the upper capacity limit of the tested tobacco thresher is about 16,000 pounds per hour. It is also noted that a given 12,500 pound per hour thresher of the prior art requires two 20 horsepower motors and one 1 V2 horsepower motor. The tested tobacco thresher, however, required only a single 25 horsepower motor even though its capacity appears to be around 16,000 pounds per hour. Moreover, the given prior art thresher has a main rotor speed of between 600 to 1200 rpm; whereas the tested thresher ran at a main rotor speed of only 450 to 750 rpm.

As noted above, the thresher of the invention also requires significantly less maintenance insofar as the wear of the cutting surfaces is concerned.

It will be appreciated by those skilled in the art that the above described results are rather startling when compared with those of the prior art. In this respect,

the principles of the invention provide a significant cost reduction for tobacco processors over the costs involved in use of prior art threshers. Moreover, the insystems can be driven by independent drive motors rather than by the single motor 56 illustrated in FIG. 6; the discs 43 need not necessarilybe round; the pins 45 can have curved surfaces; and the actual spacings need not be as set forth above.

The embodiments of the invention in which I claim an exclusive property or privilege are defined as follows:

1. A threshing machine of the type used for severing parts of harvested plants comprising:

a rotatable tooth which extends radially away from a first axis and which is rotatable about said first axis; and,

a rotatable restraining means for restraining said harvested plants so that there is relative motion between said rotatable tooth and said harvested plants, said rotatable restraining means comprising at least two coaxial discs, each having a side which faces the other disc and which has pins mounted thereon, said discs being rotatable about a second axis and being positioned to intermesh with said rotatable tooth,

whereby, said rotatable restraining means restrains motion of said harvested plants while said rotatable tooth drives through a portion of said harvested plants.

2. A threshing machine as claimed in claim 1 wherein said rotatable tooth is positioned to pass between at least two discs when rotating.

3. A threshing machine of the type used for severing parts of harvested plants comprising:

a rotatable tooth which extendsra'dially away from a first axis and which'is rotatable about said first axis; and,

a restraining means for restraining said harvested plants so that there is relative motion between said rotatable tooth and said harvested plants, said restraining means being positioned to interrnesh with said rotatable tooth, and said restraining means including:

a movable pin which is positioned crosswise to said rotatabletooth and being movable relative to said first axis.

4. A threshing machine as claimed in claim 3 wherein said restraining means includes at least two movable pinswhich are positioned crosswise to said rotatable tooth and which are positioned so that said rotatable tooth passes between them when said rotatable tooth rotates.

5. A threshing machine as claimed in claim 4 wherein there are two groups of movable pins between which said rotating tooth passes while rotating.

6. A threshing machine as claimed in claim 5 wherein said restraining means includes two surfaces which face one another and wherein each of said groups of movable pins are respectively mounted on one of said surfaces.

7. A threshing machine as claimed in claim 6 wherein said restraining means includes at least two adjacent discs, said surfaces respectively forming the sides of adjacent discs.

8. A threshing machine as claimed in claim 7 wherein said adjacent discs are rotatable in an angular direction opposite to the angular direction in which said rotatable tooth is rotatable.

9. A tobacco threshing machine of the type used for threshing tobacco comprising first and second threshing systems, each of which includes:

intermeshing first and second tobacco severing 4 an angular velocity regulating means for regulating the angular velocity of said first tobacco severing means relative to said second tobacco severing means and relative to the first and second severing means of said other threshing system.

10. A tobacco threshing machine as claimed in claim 9 wherein:

said first tobacco severing means comprises rotatable disc shaped members; and,

said second tobacco severing means comprises rotatable teeth which extend radially away from said second axes of rotation.

11. A tobacco threshing machine as claimed in claim 10 and further including a driving means for rotating said rotatable disc shaped members at a lesser angular velocity than said rotatable teeth.

12. A tobacco threshing machine as claimed in claim 11 wherein the ratios of the angular velocities of the rotatable teeth to the angular velocities of the rotatable disc shaped members, provided by said driving means,

are greater than 2.5 but less than 7.5.

13. A tobacco threshing machine as claimed in claim 12 wherein each said first tobacco severing means comprises at least two coaxial discs, each of said discs having a side which faces an adjacent disc, and further including pins which are mounted on said sides.

14. A tobacco threshing machine as claimed in claim 13 wherein said rotatable teeth are positioned to pass between said at least two coaxial discs when rotating.

15. A method of threshing tobacco comprising the steps of:

driving said tobacco in a path utilizing a side of an elongated instrument moving in a plane; and, simultaneously restraining the motion'of said driven tobacco along said path with pins which are disposed crosswise to said plane of said elongated instrument and have motion relative to said path.

16. A method of threshing tobacco as claimed in claim'15 wherein said driven tobacco is driven along a circular path about a first axis.

17. A method of threshing tobacco as claimed in claim 15 wherein the motion of said pins is provided by simultaneously rotating said pins about a second axis.

18. A method of threshing tobacco as claimed in claim 16 wherein said first and second axes are substantially parallel.

19 .'A method of threshing tobacco as claimed in claim 17 wherein said tobacco is driven in a circular path at a greater angular velocity than said pins are rotated.

l060ll 0443 

1. A threshing machine of the type used for severing parts of harvested plants comprising: a rotatable tooth which extends radially away from a first axis and which is rotatable about said first axis; and, a rotatable restraining means for restraining said harvested plants so that there is relative motion between said rotatable tooth and said harvested plants, said rotatable restraining means comprising at least two coaxial discs, each having a side which faces the other disc and which has pins mounted thereon, said discs being rotatable about a second axis and being positioned to intermesh with said rotatable tooth, whereby, said rotatable restraining means restrains motion of said harvested plants while said rotatable tooth drives through a portion of said harvested plants.
 2. A threshing machine as claimed in claim 1 wherein said rotatable tooth is positioned to pass between at least two discs when rotating.
 3. A threshing machine of the type used for severing parts of harvested plants comprising: a rotatable tooth which extends radially away from a first axis and which is rotatable about said first axis; and, a restraining means for restraining said harvested plants so that there is relative motion between said rotatable tooth and said harvested plants, said restraining means being positioned to intermesh with said rotatable tooth, and said restraining means including: a movable pin which is positioned crosswise to said rotatable tooth and being movable relative to said first axis.
 4. A threshing machine as claimed in claim 3 wherein said restraining means includes at least two movable pins which are positioneD crosswise to said rotatable tooth and which are positioned so that said rotatable tooth passes between them when said rotatable tooth rotates.
 5. A threshing machine as claimed in claim 4 wherein there are two groups of movable pins between which said rotating tooth passes while rotating.
 6. A threshing machine as claimed in claim 5 wherein said restraining means includes two surfaces which face one another and wherein each of said groups of movable pins are respectively mounted on one of said surfaces.
 7. A threshing machine as claimed in claim 6 wherein said restraining means includes at least two adjacent discs, said surfaces respectively forming the sides of adjacent discs.
 8. A threshing machine as claimed in claim 7 wherein said adjacent discs are rotatable in an angular direction opposite to the angular direction in which said rotatable tooth is rotatable.
 9. A tobacco threshing machine of the type used for threshing tobacco comprising first and second threshing systems, each of which includes: intermeshing first and second tobacco severing means for rotating about first and second axes to cooperate to thresh tobacco; and, an angular velocity regulating means for regulating the angular velocity of said first tobacco severing means relative to said second tobacco severing means and relative to the first and second severing means of said other threshing system.
 10. A tobacco threshing machine as claimed in claim 9 wherein: said first tobacco severing means comprises rotatable disc shaped members; and, said second tobacco severing means comprises rotatable teeth which extend radially away from said second axes of rotation.
 11. A tobacco threshing machine as claimed in claim 10 and further including a driving means for rotating said rotatable disc shaped members at a lesser angular velocity than said rotatable teeth.
 12. A tobacco threshing machine as claimed in claim 11 wherein the ratios of the angular velocities of the rotatable teeth to the angular velocities of the rotatable disc shaped members, provided by said driving means, are greater than 2.5 but less than 7.5.
 13. A tobacco threshing machine as claimed in claim 12 wherein each said first tobacco severing means comprises at least two coaxial discs, each of said discs having a side which faces an adjacent disc, and further including pins which are mounted on said sides.
 14. A tobacco threshing machine as claimed in claim 13 wherein said rotatable teeth are positioned to pass between said at least two coaxial discs when rotating.
 15. A method of threshing tobacco comprising the steps of: driving said tobacco in a path utilizing a side of an elongated instrument moving in a plane; and, simultaneously restraining the motion of said driven tobacco along said path with pins which are disposed crosswise to said plane of said elongated instrument and have motion relative to said path.
 16. A method of threshing tobacco as claimed in claim 15 wherein said driven tobacco is driven along a circular path about a first axis.
 17. A method of threshing tobacco as claimed in claim 15 wherein the motion of said pins is provided by simultaneously rotating said pins about a second axis.
 18. A method of threshing tobacco as claimed in claim 16 wherein said first and second axes are substantially parallel.
 19. A method of threshing tobacco as claimed in claim 17 wherein said tobacco is driven in a circular path at a greater angular velocity than said pins are rotated.
 20. A method of threshing tobacco as claimed in claim 19 wherein the ratio of the angular velocity at which the tobacco is driven to the angular velocity at which the pins are rotated is greater than 2.5 but less than 7.5. 